normal nozzle size is 0.4mm i seldom print with different sizes. But give it a try, and share it with us! ;)
Wider nozzle size decreased the overall end quality. but you can prints faster.
For me personally 18-23 hours is a very normal print time. When I print my marble machine myself, it take 35 hours.
And i have had many print that were even longer then this. ;)